Short version is it "fixed itself"
I was on the way to the dealership (since they could look at it right away) and had to do an emergency stop. The pushed to clutch in fast, and after that the feel was almost back to normal.
Tonkin Nissan quoted 110 to replace the master, which isn't bad at all since that's the price of the part alone. They said they'd replace it for free if it's defective, even though I told them it may be worn prematurely from the stiffer clutch. They said it would be covered on a 6 yr /70k warantee.
They had it up on the lift and said no air bubbles and felt fine,no need to replace it. At least they didn't charge me at all. Worst case is they drained and replaced some of my motul fluid.
I'll probably replace the master someday soon just for piece of mind.